In recent years, it has become well-known to prepare and serve beverages and other liquid food products by means of single-serving capsule-based beverage-dispensing systems. In such systems, a single-serving amount of at least one beverage ingredient, such as powdered or ground coffee, tea leaves, or cocoa powder, is provided in a single-use package, fabricated from e.g. plastic or aluminium, which is hermetically sealed to protect the beverage ingredient therein.
Such ingredient package may be a rigid or a semi-rigid capsule, a sachet, a soft pad, a pod, etc.
Such systems may also be adapted to provide servings of liquid or semi-liquid foodstuffs such as broth or baby formula; for the purposes of this document, the term “beverage” should therefore be understood as comprising any substantially-liquid alimentary substance.
To extract the beverage, the capsule is inserted into a beverage machine adapted to receive it in an ingredient package holder; the machine generally comprises a reservoir of water and means for heating the water, pressurizing it, and introducing it into the beverage package. The exact parameters of the process (e.g. temperature, water volume, injection pressure) are adapted to the type of beverage being prepared.
Upon being introduced into the package, the water mixes with the beverage ingredient and the resulting beverage is subsequently dispensed into a container for consumption. In this way, a single machine can provide single portions of a number of different beverages, on demand and with no substantial adaptation to pass from one type of beverage to another.
In many of these beverage-dispensing systems, the water is introduced into the ingredient package by means of a hollow needle. The needle pierces the ingredient package, such that during extraction a flow of water is conducted from the reservoir through the needle and into ingredient package. The flow of water mixes with the beverage ingredient to form the beverage, which is then drained from the package through at least one opening in the package provided for that purpose.
Needle-based systems permit the water to be injected at high pressures, which is advantageous in the preparation of certain beverages such as espresso coffee, or also beverages prepared on the basis of a water-soluble ingredient powder. In this last case, high velocity of the water entering into the ingredient package is beneficial to the dissolution as it enhances mixing between the soluble powder and the water. A powerful jet of water injected through the needle into the ingredient package reduces the risk of undissolved powder and subsequent clogging of the ingredient package and/or poor in-cup quality.
However, such systems also present certain disadvantages. At the end of the beverage preparation cycle, a small quantity of water remains in the needle. When hard water (i.e. water with a high content of dissolved minerals) is used, this small quantity of water remaining in the needle leaves deposits of lime scale on the interior surface of the needle as it dries. The interior diameter of the needle is thereby slowly reduced, reducing the rate at which water flows through the needle and diminishing the performance of the beverage machine. Over time, the risk of clogged needles increases, which prevents the injection of water into the ingredient packages and obligates repair or replacement of the beverage preparation machine.
This problem is particularly acute when heated (≥60° C.) water is used in the beverage preparation machine, as is the case when preparing hot beverages such as coffee or tea. Heated water causes the minerals dissolved therein to accrete on the inside of the hollow injection needle faster, exacerbating the problem beyond the levels found in cold-water (or ambient-temperature water).
Certain other systems have attempted to remedy this. For instance, the document WO 2012/076483 describes a mechanical system which comprises a pin configured to be inserted into the injection needle when a beverage capsule is inserted and removed. Such a system will indeed remove accreted mineral deposits from the inside of the injection needle, however it does not preventively expel liquids that are present on the internal surface of the needle bore after each injection cycle. Its use further requires a number of specialized components, some of which may be small and delicate, rendering the machine less reliable and more expensive to manufacture.
It is thus an object of the present invention to resolve or ameliorate at least some of the issues mentioned above.